So today I went and replaced my 66cc's regular head with the slant head on the only bike I've made thus far with the stock hardware. (Already some of you are shaking your head.) As I was getting the very last nut tightened POW!! the bolt snapped. I'm guessing there is a way to tap the screw with a bit of some sort to get the dang thing out, but I don't have the slightest idea what that bit would be called, so I'm giving a shout and saying UNCLE! Also now looking for a solid replacement set for those 4 screws..